Autocrine stimulation of rhadinovirus-transformed T cells by the chemokine CCL1/I-309

Proteome Analysis for Inflammation Related to Acute and Convalescent Infection

Infectious diseases are a significant burden in global healthcare. Pathogens engage with different host defense mechanisms. However, it is currently unknown if there are disease-specific immune signatures and/or if different pathogens elicit common immune-associated molecular entities to common therapeutic interventions. We studied patients enrolled through the Human Immunology Project Consortium (HIPC), which focuses on immune responses to various infections. Blood samples were collected and analyzed from patients during infection and follow-up time points at the convalescent stage. The study included samples from patients with Lyme disease (LD), tuberculosis (TB), malaria (MLA), dengue virus (DENV), and West Nile virus (WNV), as well as kidney transplant patients with cytomegalovirus (CMV) and polyomavirus (BKV) infections. Using an antibody-based assay, we quantified ~ 350 cell surface markers, cytokines, and chemokines involved in inflammation and immunity. Unique protein signatures were identified specific to the acute phase of infection irrespective of the pathogen type, with significant changes during convalescence. In addition, tumor necrosis factor receptor superfamily member 6 (TNR6), C-C Motif Chemokine Receptor 7 (CCR7), and C-C motif chemokine ligand-1 (CCL1) were increased in the acute and convalescent phases across all viral, bacterial, and protozoan compared to blood from healthy donors. Furthermore, despite the differences between pathogens, proteins were enriched in common biological pathways such as cell surface receptor signaling pathway and response to external stimulus. In conclusion, we demonstrated that irrespective of the pathogen type, there are common immunoregulatory and proinflammatory signals.

Circulating inflammatory factors associated with worse long-term prognosis in colorectal cancer

AIM

To investigate association of circulating inflammatory factors at the time of colorectal cancer (CRC) surgery with survival.

METHODS

Plasma levels from 174 CRC patients (69 females and 105 men), with median age 70 years (range 29-90), localized in the colon (n = 105) or rectum (n = 69), with stage I (n = 24), stage II (n = 54), stage III (n = 67) and stage IV (n = 29) were measured using commercially available Bio-Plex Pro™ Human Chemokine Panel 40-Plex, including 40 different chemokines, cytokines and interleukins. The prognostic association of each inflammatory factor was analysed as CRC-specific and total mortality.

RESULTS

Out of 174 patients, 66 died during the follow-up, 40 because of CRC specific mortality. High tertile levels of 8 factors were significantly associated with increased CRC-specific mortality, of which CCL1, CCL20, CCL24, CX3CL1, IL-4 and TNF-α remained significant in a multivariate Cox regression analysis. High tertile levels of 14 factors were associated with increased total mortality, of which CCL1, CCL15, CCL20, CX3CL1, CXCL13, IFN-γ, IL-2, IL-4 and IL-10 remained significant after adjustment for clinical covariates. For most of the inflammatory factors the association between higher tertile levels and an increased mortality in general appeared two years after surgery. High tertile levels of TNF-α and CCL24 were exclusively associated with CRC-specific mortality. The distribution of these factors were not associated with TNM stage with exception for CCL20.

CONCLUSION

High plasma levels of inflammatory factors are associated with increased risk of mortality among CRC patients and could be potential biomarkers for revealing prognosis.

Tumor cell entry into the lymph node is controlled by CCL1 chemokine expressed by lymph node lymphatic sinuses

Lymphatic vessels are thought to contribute to metastasis primarily by serving as a transportation system. It is widely believed that tumor cells enter lymph nodes passively by the flow of lymph. We demonstrate that lymph node lymphatic sinuses control tumor cell entry into the lymph node, which requires active tumor cell migration. In human and mouse tissues, CCL1 protein is detected in lymph node lymphatic sinuses but not in the peripheral lymphatics. CCR8, the receptor for CCL1, is strongly expressed by human malignant melanoma. Tumor cell migration to lymphatic endothelial cells (LECs) in vitro is inhibited by blocking CCR8 or CCL1, and recombinant CCL1 promotes migration of CCR8(+) tumor cells. The proinflammatory mediators TNF, IL-1β, and LPS increase CCL1 production by LECs and tumor cell migration to LECs. In a mouse model, blocking CCR8 with the soluble antagonist or knockdown with shRNA significantly decreased lymph node metastasis. Notably, inhibition of CCR8 led to the arrest of tumor cells in the collecting lymphatic vessels at the junction with the lymph node subcapsular sinus. These data identify a novel function for CCL1-CCR8 in metastasis and lymph node LECs as a critical checkpoint for the entry of metastases into the lymph nodes.

C-terminal clipping of chemokine CCL1/I-309 enhances CCR8-mediated intracellular calcium release and anti-apoptotic activity

Carboxypeptidase M (CPM) targets the basic amino acids arginine and lysine present at the C-terminus of peptides or proteins. CPM is thought to be involved in inflammatory processes. This is corroborated by CPM-mediated trimming and modulation of inflammatory factors, and expression of the protease in inflammatory environments. Since the function of CPM in and beyond inflammation remains mainly undefined, the identification of natural substrates can aid in discovering the (patho)physiological role of CPM. CCL1/I-309, with its three C-terminal basic amino acids, forms a potential natural substrate for CPM. CCL1 plays a role not only in inflammation but also in apoptosis, angiogenesis and tumor biology. Enzymatic processing differently impacts the biological activity of chemokines thereby contributing to the complex regulation of the chemokine system. The aim of the present study was to investigate whether (i) CCL1/I-309 is prone to trimming by CPM, and (ii) the biological activity of CCL1 is altered after C-terminal proteolytic processing. CCL1 was identified as a novel substrate for CPM in vitro using mass spectrometry. C-terminal clipping of CCL1 augmented intracellular calcium release mediated by CCR8 but reduced the binding of CCL1 to CCR8. In line with the higher intracellular calcium release, a pronounced increase of the anti-apoptotic activity of CCL1 was observed in the BW5147 cellular model. CCR8 signaling, CCR8 binding and anti-apoptotic activity were unaffected when CPM was exposed to the carboxypeptidase inhibitor DL-2-mercaptomethyl-3-guanidino-ethylthiopropanoic acid. The results of this study suggest that CPM is a likely candidate for the regulation of biological processes relying on the CCL1-CCR8 system.

Inhibition of CCL1-CCR8 interaction prevents aggregation of macrophages and development of peritoneal adhesions

Peritoneal adhesions are a significant complication of surgery and visceral inflammation; however, the mechanism has not been fully elucidated. The aim of this study was to clarify the mechanism of peritoneal adhesions by focusing on the cell trafficking and immune system in the peritoneal cavity. We investigated the specific recruitment of peritoneal macrophages (PMphi) and their expression of chemokine receptors in murine models of postoperative and postinflammatory peritoneal adhesions. PMphi aggregated at the site of injured peritoneum in these murine models of peritoneal adhesions. The chemokine receptor CCR8 was up-regulated in the aggregating PMphi when compared with naive PMphi. The up-regulation of CCR8 was also observed in PMphi, but not in bone marrow-derived Mphi, treated with inflammatory stimulants including bacterial components and cytokines. Importantly, CCL1, the ligand for CCR8, a product of both PMphi and peritoneal mesothelial cells (PMCs) following inflammatory stimulation, was a potent enhancer of CCR8 expression. Cell aggregation involving PMphi and PMCs was induced in vitro in the presence of CCL1. CCL1 also up-regulated mRNA levels of plasminogen activator inhibitor-1 in both PMphi and PMCs. CCR8 gene-deficient mice or mice treated with anti-CCL1-neutralizing Ab exhibited significantly reduced postoperational peritoneal adhesion. Our study now establishes a unique autocrine activation system in PMphi and the mechanism for recruitment of PMphi together with PMCs via CCL1/CCR8, as immune responses of peritoneal cavity, which triggers peritoneal adhesions.

Transformation by herpesviruses: focus on T cells

Acute T-lymphoproliferative syndromes are caused by herpesvirus saimiri (HVS) and ateles in neotropical primates; by alcelaphine herpesvirus-1 and ovine herpesvirus-2 strains in domestic cattle and other ungulates; and by the α-herpesvirus of Marek's disease in chickens. T-cell lymphoproliferation caused by these herpesviruses has short incubation periods and a rapid course when compared with retroviral disease. The B-lymphotropic Epstein–Barr virus (EBV) is also associated with some human T-cell malignancies. Analogous to EBV in B cells, HVS isolates of the subgroup C are uniquely capable of transforming human and Old World primate T lymphocytes to continuous growth in cell culture and can provide useful tools for T-cell immunology or gene transfer. Signal transduction pathways stimulated by the viral oncoproteins seem to converge at related cellular effector proteins, in total providing a proproliferative signal. However, the viral oncoproteins most likely evolved to evade immune recognition and to support persistent infection in the natural host, where these viruses are frequently apathogenic.

Delayed polarization of mononuclear phagocyte transcriptional program by type I interferon isoforms

Background

Interferon (IFN)-α is considered a key modulator of immunopathological processes through a signature-specific activation of mononuclear phagocytes (MPs). This study utilized global transcript analysis to characterize the effects of the entire type I IFN family in comparison to a broad panel of other cytokines on MP previously exposed to Lipopolysaccharide (LPS) stimulation in vitro.

Results

Immature peripheral blood CD14+ MPs were stimulated with LPS and 1 hour later with 42 separate soluble factors including cytokines, chemokines, interleukins, growth factors and IFNs. Gene expression profiling of MPs was analyzed 4 and 9 hours after cytokine stimulation. Four hours after stimulation, the transcriptional analysis of MPs revealed two main classes of cytokines: one associated with the alternative and the other with the classical pathway of MP activation without a clear polarization of type I IFNs effects. In contrast, after 9 hours of stimulation most type I IFN isoforms induced a characteristic and unique transcriptional pattern separate from other cytokines. These "signature" IFNs included; IFN-β, IFN-α2b/α2, IFN-αI, IFN-α2, IFN-αC, IFN-αJ1, IFN-αH2, and INF-α4B and induced the over-expression of 44 genes, all of which had known functional relationships with IFN such as myxovirus resistance (Mx)-1, Mx-2, and interferon-induced hepatitis C-associated microtubular aggregation protein. A second group of type I IFNs segregated separately and in closer association with the type II IFN-γ. The phylogenetic relationship of amino acid sequences among type I IFNs did not explain their sub-classification, although differences at positions 94 through 109 and 175 through 189 were present between the signature and other IFNs.

Conclusion

Seven IFN-α isoforms and IFN-β participate in the late phase polarization of MPs conditioned by LPS. This information broadens the previous view of the central role played by IFN-α in autoimmunity and tumor rejection by including and/or excluding an array of related factors likely to be heterogeneously expressed by distinct sub-populations of individuals in sickness or in response to biological therapy.